Field of the Invention
The present invention relates to the novel attenuated vaccinia virus strain KVAC103 having reduced toxicity and side effects.
Description of the Prior Art
Vaccinia virus is an enveloped DNA virus which has an about 120-180 kb double-stranded linear DNA genome encoding about 200 different genes (Hendrickson et al., 2010). Each of the genes is composed of a short 5′-promoter, a single ORF encoding a protein without intron, a short 3′-polyadenylation site. These proteins are expressed in a promoter-dependent manner in the intermediate-early (IE), early (E) or late (L) stage of viral infection. The sequences of the early and late promoters have been well characterized through functional experiments (Rosel et al., 1986; Yuen et al., 1987; Davision et al., 1989a and 1989b; Chakrabarti et al., 1997).
Since vaccinia virus was first used as a vaccine for smallpox by Edward Jenner in the 18th century, it has become a general term for immunomodulators such that it would give the etymology of the word “vaccine”. Smallpox is an acute contagious disease caused by the variola virus. In smallpox caused by the variola major virus, maculopapular exanthema appears after an incubation of 7-17 days (12 days on average), and then progresses to blisters, pus blisters, etc. Smallpox has a mortality rate of 30% or higher, and the survivors are left with scars on the face. The variola virus that causes smallpox belongs to the Orthopoxvirus genus together with monkeypox, cowpox and vaccinia virus. Orthopoxviruses have the characteristic of inducing strong cross-immunity therebetween, and thus a vaccine produced from the vaccinia virus, which is less pathogenic than variola virus, has been used in a global program for the eradication of smallpox. The effect of the vaccine was demonstrated by the 1980's World Health Organization (WHO) declaration of eradication of smallpox (WHO Declaration of global eradication of smallpox, WkIy Epideminol Rec 1980:55:148). The variola virus that causes smallpox is characterized in that: 1) it is stable in an aerosol state; 2) it is easy to mass-produce; 3) it is contagious in a small amount; 4) it is highly contagious among humans; 5) it has a long incubation period of 7-17 days; and 6) it has high mortality rate. Due to such characteristics, there have been concerns over the potential for the variola virus to be developed as biological weapons. Due to the uncertainty over the eradication of smallpox and the danger of developing the variola virus into biological terror weapons, countries have retained smallpox vaccines for use in case of emergency. As is known, in the case of the USA, the first-generation smallpox vaccine produced from cows has been used for some risk groups. Some developed countries including Japan have also taken their own measures, and for example, developed smallpox vaccine by themselves in order to meet the demand for smallpox vaccines in their countries, or purchased the first-generation smallpox vaccine.
Vaccinia virus used in the early years had a good immunogenic efficacy and greatly contributed to the eradication of smallpox, but people vaccinated with the vaccinia virus sometimes showed serious side effects such as systemic infection or progressive infection. To reduce such side effects, Virulence-attenuated vaccinia virus strains including MVA, NYVAC, and LC16m8 were developed. Among them, modified vaccinia virus Ankara (MVA) as disclosed in Korean Patent No. 1009102970000 is an attenuated virus strain obtained by Subculturing the vaccinia virus CVA strain 500 times or more in chick embryo fibroblasts (CEFs), and it does not proliferate in most mammalian cells and has a 30 kb deleted region in six regions in the genome. This virus showed excellent safety in animal models, and thus have been developed as a smallpox vaccine and a vaccine delivery vehicle by Bavarian Nordic (Denmark). LC16m8, an attenuated virus developed by the Chiba Serum Institute of Japan, forms small plaques and shows reduced virulence. It was found to have a mutation in the B5R gene in the genome sequence. NYVAC is a virus strain obtained by deleting 18 ORFs from five regions containing 18 ORFs in the genome of the Copenhagen strain by a genetic engineering technique, and has been developed as various recombinant viral delivery vehicles.